Topic 4: Key Questions
Use your knowledge and understanding learned during Topic 4 to answer the following questions in as much detail as you can (essay style) Why are rabbits such a pest in Australia? Rabbits, like most other pest species, were introduced when Europeans first settled in Australia. Rabbits were introduced from two main sources; the domesticated rabbit which provided early settlers with a ready source of meat, and the wild rabbit introduced later for hunting. Thomas Austin is credited with releasing 24 wild rabbits at his Barwon Park property near Geelong in Victoria in 1859. This small population exploded to cover Victoria and New South Wales by 1886. By 1900, rabbits had reached the Northern Territory and Western Australia. In some other areas, feral domesticated rabbits also established populations. Typically, these rabbits have different colourings compared to the wild rabbits released by Thomas Austin. The rapid spread of the rabbit led to the destruction of large tracts of vegetation, leading to the extinction of many plant species. Loss of vegetation leads to soil erosion as the exposed soil is washed or blown away, removing valuable soil nutrients required for new plants to develop. This soil is typically deposited in waterways, causing siltation and destroying aquatic ecosystems. wiki image 5.jpg|link=Why are rabbits a pest in Australia Why is territory so important for animals? Territoriality is a type of intraspecific or interspecific competition that results from the behavioral exclusion of others from a specific space that is defended as territory. This well-defined behavior is exhibited through songs and calls, intimidation behavior, attack and chase, and marking with scents. This form of defense proves to be very costly for animals. An animal chooses its territory by deciding what part of its home range it would like to defend. In selecting a territory the size and the quality play a crucial role in determining an animals habitat. Territory size generally tends to be no larger than the organism than requires to survive, because with an increase in territory comes an increased in energy expenditure. For some animals the territory size is not the most important aspect of territoriality, but rather the quality of defended territory. The quality is considered to be fundamentally important due to amount of food availability and superior nesting sights. Animals depend on these features to ensure their superior fitness. Animals invest a lot of time and energy in defending their territories, and for this reason they fight vigorously to defend their territory at all cost. Researchers suggest for this reason that when a rival challenges a territory holder, the owner almost always wins the contest. This phenomenon could be attributed to an evolutionary stable strategy which assets that rules for behavior is controlled by an inherited proximate mechanism such that the differences between individuals in their strategies are liked to differences in their genes. Territory plays an important role as a mechanism of population regulation, insuring the success of fit animals, and aiding in the eradication of less fit animals. Territorially also plays a fundamental role as an indicator of carrying capacity; it also serves as an indicator of how much habitat is necessary to support viable populations. wiki image 2.jpg|Wild cats fighting over territory|link=Why is territory so important to animals? wiki image 3.jpg|Wild bears fighting over territory|link=Why is territory so important to animals? Hippos fighting for territory.jpg|Wild Hippos fighting for territory If animals fight over land and mating partners, what do plants fight over? Plants fight over sunlight for photosynthesis, water also for photosynthesis, CO2 and space to help them grow and nutrients in the soil for food. Why is there a variety of birds in the park and not just one species? Why did dinosaurs become extinct? The most popular idea of why the dinosaurs become extinct is the Asteroid Theory. According to this theory a large asteroid or comet collided with Earth about 65 million years ago. Scientists think that such a large collision would throw so much dust into the air that sunlight would not be able to shine and plants and animals would die. The dramatic changes in climate that resulted from this huge collision were too much for the dinosaurs. They were not able to survive. Another theory that could explain how the dinosaurs became extinct is volcanic activity. A huge increase in volcanic activity at around 65 millions years ago could have pumped so much ash into the air that it blocked out the sun killing the dinosaurs. Some scientists believe that there was a severe ice age. Throughout Earth's history there have been many ice ages. The last one ended about 10,000 years ago. A very severe ice age could have changed temperatures and frozen a lot of Earth's water. The dinosaurs would not be able live under such conditions and that is how the dinosaurs became extinct. There are probably other theories as to how the dinosaurs became extinct. One thing is for certain. All dinosaurs that we know of are extinct. How did all the dinosaurs become extinct? Maybe one of these theories is the right answer. However, it is difficult to explain why all the dinosaurs died out but many other animals survived. Triceratops.jpg|Triceratops|link=Why did dinosaurs become extinct? T-Rex.jpg|Tyrannosaurus Rex|link=Why did dinosaurs become extinct? T-Rex Skeleton.jpg|Tyrannosaurus Rex Skeleton|link=Why did the dinosaurs become extinct? Pterodactyl.jpg|Pterodactyl|link=Why did dinosaurs become extinct? Why do deep-sea fish have cylindrical eyes and not eyeballs? The fish of the deep sea are among the strangest and most elusive creatures on Earth. In this deep unknown lie many unusual creatures we still have yet to study. Since many of these fish live in regions where there is no natural illumination, they cannot rely solely on their eyesight for locating prey and mates and avoiding predators; deep sea fish have evolved appropriately to the extreme sub-photic region in which they live. Many deep sea fish are bioluminescent, with extremely large eyes adapted to the dark. Some have long feelers to help them locate prey or attract mates in the pitch black of the deep ocean. The deep sea angler fish in particular has a long fishing-rod-like adaptation protruding from its face, on the end of which is a bioluminescent piece of skin that wriggles like a worm to lure its prey. The lifecycle of deep sea fish can be exclusively deep water although some species are born in shallower water and sink on becoming born. Due to the poor level of photosynthetic light reaching deep sea environments, most fish need to rely on organic matter sinking from higher levels, or, in rare cases, hydrothermal vents for nutrients. This makes the deep sea much poorer in productivity than shallower regions. Consequently many species of deep sea fish are noticeably smaller and have larger mouths and guts than those living at shallower depths. It has also been found that the deeper a fish lives, the more jelly-like its flesh and the more minimal its bone structure. This makes them slower and less agile than surface fish. A example of weird eyes is the Macropinna microstoma fish. The eyes get the name "barreleyes" because it's are cylindrical, rather than spherical; this is an adaptation for better light collection in the dim depths where it lives, using very large lenses but not building a giant spherical eye to compensate. It's ore like a telescope than a wide-angle camera. wiki image 1.jpg|Macropinna microstoma,|link='Why do fish have cylindrical eyes and no eye balls.' Why are all conservation initiatives not equally successful? Why is recycling of materials encouraged? As humans we are constanty looking for ways to improve our lifestyle. For example the car. Cahnged from horse and cart to motorised vechile. We have found a great way of getting somewhere quickly and in compfort. Unfortunantly it causes pollution andhas an effect on global warming. So as we humans have created global warming we have also made a solution. Recycling, re-using materials e.g cardboard, plastic and glass. |ndistries promote recycling and re-using materials also helps the environment as we are causing less damage to the environment. There are over 5,000 bottle banks in the U.K. All local authorities have a bottle bank scheme. Bottle banks are placed in convenient places for the public, such as near supermarkets and civic centres. The banks are emptied by special vehicles which have compartments for the different colour of glass. When there is sufficient quantity it is loaded and taken to the recycling plant. Glass recycling saves energy in the production of raw materials, and the melting of the glass. Saving this amount of energy is the equivalent to 30 gallons of oil for every tonne of cullet added to the batch of raw materials. Using recycled paper reduces water use and water pollution, e.g. the British paper and board industry is one of the countrys largest industrial users of water. For many countries without large domestic sources of pulp wood, the major economic advantage of recycling is in reducing the need to use imported pulp. It is estimated that between 10-17 trees are needed to produce a tonne of paper, this is enough for 7000 copies of national newspaper. wiki image 4.jpg|link=Why is recycling important? Category:B2 Category:Biology Category:Questions Category:AQA Category:Essay questions Category:recycling Category:Dinosaurs Category:Rabbits